Our colleagues at KQED live blogged as the story unfolded. They report there was at least one injury: A firefighter "suffered burns to his face and hands." The city's fire chief, Joanne Hayes-White, tells local news outlets that this was the city's biggest fire in at least several years.

According to the Chronicle, "fire investigators believe that whatever sparked the blaze had as long as an hour to smolder. The building's sprinkler system had not yet been installed." Construction was set to be completed later this year.